udev: Move udev_block() and udev_unblock() into udev.c

Add kernel style comments and better error handling.

Signed-off-by: Mateusz Grzonka <mateusz.grzonka@intel.com>
Signed-off-by: Kinga Tanska <kinga.tanska@intel.com>
Signed-off-by: Jes Sorensen <jes@trained-monkey.org>

1 files changed, 44 insertions, 0 deletions

diff --git a/udev.c b/udev.c
index 2bac6921..bc4722b0 100644
--- a/udev.c
+++ b/udev.c
@@ -28,6 +28,8 @@
 #include	<syslog.h>
 #include	<libudev.h>
 
+static char *unblock_path;
+
 /*
  * udev_is_available() - Checks for udev in the system.
  *
@@ -148,3 +150,45 @@ enum udev_status udev_wait_for_events(int seconds)
 	return UDEV_STATUS_TIMEOUT;
 }
 #endif
+
+/*
+ * udev_block() - Block udev from examining newly created arrays.
+ *
+ * When array is created, we don't want udev to examine it immediately.
+ * Function creates /run/mdadm/creating-mdXXX and expects that udev rule
+ * will notice it and act accordingly.
+ *
+ * Return:
+ * UDEV_STATUS_SUCCESS when successfully blocked udev
+ * UDEV_STATUS_ERROR on error
+ */
+enum udev_status udev_block(char *devnm)
+{
+	int fd;
+	char *path = xcalloc(1, BUFSIZ);
+
+	snprintf(path, BUFSIZ, "/run/mdadm/creating-%s", devnm);
+
+	fd = open(path, O_CREAT | O_RDWR, 0600);
+	if (!is_fd_valid(fd)) {
+		pr_err("Cannot block udev, error creating blocking file.\n");
+		pr_err("%s: %s\n", strerror(errno), path);
+		free(path);
+		return UDEV_STATUS_ERROR;
+	}
+
+	close(fd);
+	unblock_path = path;
+	return UDEV_STATUS_SUCCESS;
+}
+
+/*
+ * udev_unblock() - Unblock udev.
+ */
+void udev_unblock(void)
+{
+	if (unblock_path)
+		unlink(unblock_path);
+	free(unblock_path);
+	unblock_path = NULL;
+}